1G If Cam angle sensor is bad will I get a spark?

[jck]

Hello,
I have a 90 eclipse 2.0 no- turbo.
The car will not start,but was driven daily until no start issue.
I have checked fusible links at battery and fuses in fuse panel.
The fuses are not blown.
I have checked ignition by replacing coil, wires ,plugs and power transistor.
Also, the fuel pressure has been checked and fpr has been changed out.
Also, the coolant temp sensor was found to be defective, but it was replaced. The TPS is bad, but not far out of range. I have checked TPS and it has a closed throttle plate value this was ok, but the resistance value when opening and closing the throttle plate is a little off, but not by much. I do not believe the TPS is causing a no-start issue for this car.

When I pull the plugs, after trying to start the car they are gas fouled. Cyl. 1 and 4 are are gas fouled worse than the other plugs. I have tried using starting fluid to start car, this does not help the car start.
I have to remove spark plugs for cleaning after a couple times of trying to start the car.When I remove spark plugs to clean them cyl.1 and 4 plugs are flooded. Cyl.2 and 3 are not very bad gas fouled. I have ohmed injectors and they are ok.

This leads me to believe it is an issue with timing.
I have checked the physical timing and all cams /crank timing marks line up.
I am thinking the Cam angle sensor may be defective. I have looked in forums for answers to this no-start issue. I need a definitive way to test CAS. Some methods to test the CAS are listed in forums. But some have indicated in forums that the CAS can not be tested. Also, the Haynes manual says the CAS can not be tested.

The CAS I have is a 4 wire sensor. One wire is 12 v power, another wire is ground, the 3rd wire is the wire for determining TDC for cyl 1 and 4 and the last wire on the CAS is for CAM inputs to the ECU
My cam angle sensor does the job of crank and cam position sensors.

This is the question I have, if Cam angle sensor is bad will I get a spark.(Autozone Manager says yes, camangle sensor can be bad and car will still have spark)
I have spark on all cyl.1-4.

I have a Haynes manual, it says the CAS for my car determines the order the fuel injectors open. Also the Haynes manual says the CAS determines TDC for cylinders 1 and 4. Could the CAS be the reason the car won't start? Is there anything else that would keep the car from not starting? Is TPS the reason for the car not starting?

Any help will be greatly appreciated?
Thanks jck

 

[williamsoa]

I am picking up an engine coolant sensor tomorrow. . . hopefully this will do the trick. I have inspected and did a voltage drop test on every ignition circuit and it all came out good.

 

[williamsoa]

No change, I am just going to replace the wiring harness.

 

[honduraneclipse]

did replacing the wiring harness work? what about the new timing belt? I just experienced this same problem myself, cylinders 1 and 4 are being fuel washed. spark and fuel was tested. DSMlink v3, verifies fuel pump flow and rpm signal during cranking. just tested spark wires 10mm magnecores 4.5k ohms average and the coils are both @ 12.93k-12.95kohms. spark looked healthy with the spark tester. I tried to adjust the CAS while cranking and did not make a difference. This was all @ the body shop 30 minutes where from i live, on easter sunday with limited time to diagnose. i will double check compression and my timing marks when i come back.
E85 fuel in tank for about 2 months.
car started fine up until 2 weeks ago the shop. drove around for 2 hours after filling up tank and arriving at body shop.
1600cc fuel clinic injectors low impedance
new walbro 450lph pump
EDIT UPDATE: The CAM angle sensor signal was intermittent until it finally shit the bed, causing also the initial wash off the cylinders. The crank sensor signal is still active but not the appropiate 300-350 rpm signal at start up for the injectors to fire. I would get spark but not fuel since the cam signal was not working properly , crank RPM was @ 150rpm. The used black top CAS fired the car right up.

 

[Sasha Gironda]

Hello,
I have a 90 eclipse 2.0 no- turbo.
The car will not start,but was driven daily until no start issue.
I have checked fusible links at battery and fuses in fuse panel.
The fuses are not blown.
I have checked ignition by replacing coil, wires ,plugs and power transistor.
Also, the fuel pressure has been checked and fpr has been changed out.
Also, the coolant temp sensor was found to be defective, but it was replaced. The TPS is bad, but not far out of range. I have checked TPS and it has a closed throttle plate value this was ok, but the resistance value when opening and closing the throttle plate is a little off, but not by much. I do not believe the TPS is causing a no-start issue for this car.

When I pull the plugs, after trying to start the car they are gas fouled. Cyl. 1 and 4 are are gas fouled worse than the other plugs. I have tried using starting fluid to start car, this does not help the car start.
I have to remove spark plugs for cleaning after a couple times of trying to start the car.When I remove spark plugs to clean them cyl.1 and 4 plugs are flooded. Cyl.2 and 3 are not very bad gas fouled. I have ohmed injectors and they are ok.

This leads me to believe it is an issue with timing.
I have checked the physical timing and all cams /crank timing marks line up.
I am thinking the Cam angle sensor may be defective. I have looked in forums for answers to this no-start issue. I need a definitive way to test CAS. Some methods to test the CAS are listed in forums. But some have indicated in forums that the CAS can not be tested. Also, the Haynes manual says the CAS can not be tested.

The CAS I have is a 4 wire sensor. One wire is 12 v power, another wire is ground, the 3rd wire is the wire for determining TDC for cyl 1 and 4 and the last wire on the CAS is for CAM inputs to the ECU
My cam angle sensor does the job of crank and cam position sensors.

This is the question I have, if Cam angle sensor is bad will I get a spark.(Autozone Manager says yes, camangle sensor can be bad and car will still have spark)
I have spark on all cyl.1-4.

I have a Haynes manual, it says the CAS for my car determines the order the fuel injectors open. Also the Haynes manual says the CAS determines TDC for cylinders 1 and 4. Could the CAS be the reason the car won't start? Is there anything else that would keep the car from not starting? Is TPS the reason for the car not starting?

Any help will be greatly appreciated?
Thanks jck

Did you ever find a resolution?

 

[Sasha Gironda]

Did you find a resolution?

 

[boostdawd]

I ran into this issue myself. Car wouldn't start after replacing my valve stem seals. I thought I might have messed up the timing. Timing was dead on. After troubleshooting and verifying fuel and spark, I began to suspect the CAS.

Spark was present but appeared to be weak in my opinion. The forums helped me t/s the CAS. There are 4 wires. One for 12v, ground and 5v for cam and crank. In my case, the crank output was never close to 5v. Replacing the CAS fixed my issue. Always nice to have spares. HAPPY BOOSTING!

 

[shinzon]

One for 12v, ground and 5v for cam and crank. In my case, the crank output was never close to 5v. Replacing the CAS fixed my issue. Always nice to have spares. HAPPY BOOSTING!

To expand on this a bit, the 5 volts measured on the (for my '96) blue with a red stripe wire on the cam, and blue with white on the crank, is the 5v reference signal. This circuit is regulated internally by the ECU, and is the lifeblood of an electronic fuel injection system. This circuit provides a rock-solid voltage, insulated against fluctuations in system voltage, for the sensors to measure against. An example would be the throttle position sensor, which is on the same 5v circuit as the cam and crank sensor (every sensor that's not a thermistor is generally on the same circuit internal to the ECU). When you press the gas, the throttle actuates the TPS, which varies resistance and changes the voltage the ECU is reading on the signal wire. Since the starting voltage, 5vs, is known, the ECU can extrapolate throttle position by reading the voltage change.

Cam and crank sensors are hall effect type, which means a metal plate spins between an armature with two magnets. When the plate is in such a position where the armature is in open air, a magnetic feild is present which closes the circuit, and when the plate is between the magnets it breaks the magnetic field opening the circuit--this on-off pulsing of the 5v reference signal create a digital square wave that the ECU interprets. You cam sensor was likely shorted to ground internally, and since all MFI components that are not thermistors share the same circuit internal to the ECU, it brought down voltage in the entire reference circuit, which made it impossible for the ECU to get good readings from ANY of the MFI sensors. This is why replacing the cam sensor fixed the reference signal on the crank--it fixed it for the whole system.

 

[boostdawd]

Is there a way to fix the actual sensor? This one is a black top and I know those things are rare. I would like to salvage it if possible.

 

[shinzon]

Is there a way to fix the actual sensor? This one is a black top and I know those things are rare. I would like to salvage it if possible.

The backtop CAS was the rarer optical style? I'm not well versed in first gens... In any case, unfortunately, I don't know of any way to repair a cam sensor, optical or hall effect.

 

[BoostedTalonTS]

Is there a way to fix the actual sensor? This one is a black top and I know those things are rare. I would like to salvage it if possible.

Yes there is. The Later 1GB's came with the black top CAS. They are also hall-effect, like anything from the 2G CAS arena. They don't have any user-serviceable parts inside though, however, you can just replace the black plastic assembly that houses the crank & cam induction pick-ups, as well as the 4-pin connector... if you can find a donor CAS to lend you it's internals (it's all one piece). -I have a dead assembly that I'll snap a pic of for you, if you'd like... it's held within the CAS by x3 #2 Phillips screws. You'll have to remove the upper pick-up arms in order to access the screws though (just pay close attention to their original position & make sure that they go back in the right order, once you replace the inner sub-assembly.

The backtop CAS was the rarer optical style? I'm not well versed in first gens... In any case, unfortunately, I don't know of any way to repair a cam sensor, optical or hall effect.

No, it was the early 90-91 Green Top CAS that were optically-referenced. Unfortunately none of their internals are interchangeable with the later model Black Top CAS^

 

[BoostedTalonTS]

To the OP's original issue (from waaay back when), I'm surprised that no one has mentioned the Power Transistor Unit yet... These have also been known to go wonky & interrupt the ECU's signal that drives the coils. Since #1 & #4 are on the same coil, it could be the PTU (or any of the connections to/from it) as well. -Just another thing to consider

 

[shinzon]

No, it was the early 90-91 Green Top CAS that were optically-referenced. Unfortunately none of their internals are interchangeable with the later model Black Top CAS^

Ah, okay. Was there any advantage of optical style cam sensors over their Hall Effect counterparts? I assume Mitsubishi transitioned away from them for cost and complexity reasons.

To the OP's original issue (from waaay back when), I'm surprised that no one has mentioned the Power Transistor Unit yet... These have also been known to go wonky & interrupt the ECU's signal that drives the coils. Since #1 & #4 are on the same coil, it could be the PTU (or any of the connections to/from it) as well. -Just another thing to consider

Yup, I just had a no spark problem on 1&4 that ended up being the transistor. Guess it's not a big help for the OP all these years later.

 

[BoostedTalonTS]

Ah, okay. Was there any advantage of optical style cam sensors over their Hall Effect counterparts? I assume Mitsubishi transitioned away from them for cost and complexity reasons.

The early Green Top CAS offered a steady idle, but lost resolution in higher engine RPMs & caused sensor output variations up top (from my understanding)... so Mitsu switched it out for a hall-effect style

 

[BoostedTalonTS]

@boostdawd Here's those Black Top CAS Inner assembly pics I mentioned earlier:

https://www.dropbox.com/sh/z4vu5rlflqmxlmb/AAA-44mtHmS4QN9T0u9kcsPfa?dl=0

 

[boostdawd]

Thanks. That helps out a lot. I'll try swapping some internals around see if I can get the old one to work again.

 

[BoostedTalonTS]